The well-being of dogs used in research is contingent upon
the development and implementation of appropriate programs that
promote: disease prevention, adequate veterinary care, proper
nutrition, sound husbandry, socialization and appropriate
facilities (92). There are two factors affecting well-being:
physiological and psychological. Physiological well-being may be
defined as a state of clinical health or absence of of disease or
injury. Psychological well-being, however, is problematic in
definition because of the complexity of assessing the "mental
state" of an animal. One working definition refers to
psychological well-being as a state in which an animal is free of
distress for the most part, is in good health, exhibits a
substantial range of behaviors typical of the species and can
deal effectively with its environment (64).

Psychological well-being of dogs has been of recent concern
to biological scientists, animal protection groups, the general
public and regulatory agencies. The 1985 amendments to the Animal
Welfare Act (Public Law 99-189) directed the Animal and Plant
Health Inspection Service (APHIS) to promulgate regulations that
would require registered dealers, exhibitors and research
institutions to provide dogs with the opportunity to exercise.
All registrants must develop an institutional plan that would
satisfy regulatory requirements (1). APHIS has suggested that
opportunities for exercise may be provided in a number of
different ways. For example:

Dogs may be group housed in cages, pens or runs that provide
at least 100 per cent of the regulated space requirement for
each dog.

Individually housed dogs can be housed in cages, pens or
runs that provide at least double the minimum regulated
space required.

Dogs can be given access to a run or open space.

Dogs can be given positive physical contact with a human
which encourages exercise (e.g. play).

Treadmills, carousels, swimming or other forms of forced
exercise cannot be utilized to meet regulatory criteria since the
intent of Congress was to provide the dog with the "opportunity"
for exercise (1).

Controversy has surrounded the development of standards to
satisfy Congressional intent (2,5). Although research has been
conducted using dogs as a model for exercise physiology, little
scientific work has been conducted to determine a dog's exercise
"needs" in a physiologic and psychological sense (63,64,66,92).
However, comparative studies may be beneficial in establishing
physiological reference values of physical fitness that can be
used to further investigate physiological "need".

Many factors are thought to influence the physiological and
psychological well-being of the confined dog. Genotype, housing,
behavior, sex, breed, age and socialization have been cited as
variables (69,87,90). Of these factors housing and socialization
(animal or human) have been studied to a limited degree. To
date, studies have not been able to significantly demonstrate
that cage size affects exercise and/or physical fitness when
submaximal heart rate , muscle enzymes (O2 utilization) and
plasma cortisol (stress) are measured (63,66,70,71).

There is, however, evidence that well-socialized dogs are
more likely to be active than those that are socially deprived
(67,69,76). Socialization can be provided through conspecifics,
human contact or both. Ethological studies of wild animals have
revealed that when all physiological criteria are met through
food abundance, shelter and there is absence of predation animals
will not "exercise". The conservation of energy is of utmost
importance in wild animals and unnecessary expenditure is not a
viable strategy. Therefore exercise happens as a result of
animals satisfying other behavioral and physiological activities
(e.g. foraging for food, socializing or seeking shelter (69).
Socialization in packs for the purpose of maintaining heirarchy,
resource access and breeding priviledge may be considered one of
the activities. How this extrapolates to the confined domestic
dog has not been determined.

More research into physiological and psychological factors is
needed to fully determine their importance in maintaining a dog's
psychological well-being in a variety of environments and how to
measure those factors to determine whether needs are met
(63,64,66,67).

This Special Reference Brief (SRB) is designed to provide
bibliographic information on exercise for dogs. The SRB has been
divided into categories that are related to the subject area:
Regulatory Issues, Exercise Physiology, Environmental Physiology
and Behavior, Husbandry and Management and, Biological Reference
Values. The information in this document was derived from a
variety of information resources. All citations available from
the collection of the National Agricultural Library (NAL) will
provide the NAL call number.

Special thanks goes to Dr. J. Derrell Clark, D.V.M., University
of Georgia, School of Veterinary Medicine and to Dr. Bruce Ewald,
D.V.M. of CIBA-GIEGY for their thoughtful reviews, constructive
comments and additions to this document.